Fruit and vegetable consumption and mortality from all causes, cardiovascular disease, and cancer: systematic review and dose-response meta-analysis of prospective cohort studiesBMJ 2014; 349 doi: https://doi.org/10.1136/bmj.g4490 (Published 29 July 2014) Cite this as: BMJ 2014;349:g4490
- Xia Wang, instructor in nutrition12,
- Yingying Ouyang, research fellow2,
- Jun Liu, research fellow2,
- Minmin Zhu, instructor in biostatistics3,
- Gang Zhao, instructor in medicine4,
- Wei Bao, postdoctoral fellow5,
- Frank B Hu, professor6
- 1Department of Maternal and Child Health Care, School of Public Health, Shandong University, Jinan, China
- 2Department of Nutrition and Food Hygiene, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- 3Department of Epidemiology and Biostatistics, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- 4Department of Cardiovascular Sciences, Shandong Provincial Hospital affiliated to Shandong University, Jinan, China
- 5Epidemiology Branch, Division of Intramural Population Health Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Rockville, MD 20852, USA
- 6Departments of Nutrition and Epidemiology, Harvard School of Public Health, Boston, MA 02115, USA
- Correspondence to: F B Hu and W Bao
- Accepted 23 June 2014
Objective To examine and quantify the potential dose-response relation between fruit and vegetable consumption and risk of all cause, cardiovascular, and cancer mortality.
Data sources Medline, Embase, and the Cochrane library searched up to 30 August 2013 without language restrictions. Reference lists of retrieved articles.
Study selection Prospective cohort studies that reported risk estimates for all cause, cardiovascular, and cancer mortality by levels of fruit and vegetable consumption.
Data synthesis Random effects models were used to calculate pooled hazard ratios and 95% confidence intervals and to incorporate variation between studies. The linear and non-linear dose-response relations were evaluated with data from categories of fruit and vegetable consumption in each study.
Results Sixteen prospective cohort studies were eligible in this meta-analysis. During follow-up periods ranging from 4.6 to 26 years there were 56 423 deaths (11 512 from cardiovascular disease and 16 817 from cancer) among 833 234 participants. Higher consumption of fruit and vegetables was significantly associated with a lower risk of all cause mortality. Pooled hazard ratios of all cause mortality were 0.95 (95% confidence interval 0.92 to 0.98) for an increment of one serving a day of fruit and vegetables (P=0.001), 0.94 (0.90 to 0.98) for fruit (P=0.002), and 0.95 (0.92 to 0.99) for vegetables (P=0.006). There was a threshold around five servings of fruit and vegetables a day, after which the risk of all cause mortality did not reduce further. A significant inverse association was observed for cardiovascular mortality (hazard ratio for each additional serving a day of fruit and vegetables 0.96, 95% confidence interval 0.92 to 0.99), while higher consumption of fruit and vegetables was not appreciably associated with risk of cancer mortality.
Conclusions This meta-analysis provides further evidence that a higher consumption of fruit and vegetables is associated with a lower risk of all cause mortality, particularly cardiovascular mortality.
We thank Fuzhong Xue (director and professor of statistics, School of Public Health, Shandong University) for providing statistical advice.
Contributors: XW, GZ, YYO, and FBH contributed to conception and design. All authors were involved in analysis and interpretation of the data. MMZ, XW, and WB designed and conducted the statistical analysis. XW, JL, WB, and GZ drafted the manuscript, which was critically revised for important intellectual content by XW, WB, and FBH. All authors approved the final version. FBH is guarantor.
Funding: This work was funded by National Natural Science Foundation (NSFC 81071081) of China. WB was supported by the Intramural Research Program of the Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health. The funders had no role in study design, data collection and analysis, preparation of the manuscript, or decision to publish.
Competing interests: All authors have completed the ICMJE uniform disclosure form at www.icmje.org/coi_disclosure.pdf (available on request from the corresponding author) and declare: no support from any organization for the submitted work; no financial relationships with any organizations that might have an interest in the submitted work in the previous three years; and no other relationships or activities that could appear to have influenced the submitted work.
Ethical approval: Not required.
Data sharing: No additional data available.
Transparency: The lead author (the manuscript’s guarantor) affirms that this manuscript is an honest, accurate, and transparent account of the study being reported; that no important aspects of the study have been omitted; and that any discrepancies from the study as planned and registered have been explained.
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